. >> reporter: and what happened at this school outside boston, an extreme example, but entirely legal. >> some day, we're all -- i think we're all going to look back, and we're going to say, "can you believe what we did here?" >> reporter: an abc news investigation has found that only 17 states have specific laws protecting students from harsh treatments and restraints. >> there's thousands and thousands of children that have been traumatized, they have been injured. >> reporter: in arizona and washington state, parents are up in arms over padded isolation boxes or cells, where students have been left for long stretches. in kentucky, a mother found her autistic 8-year-old son had been stuffed into a duffel bag like this one, specially made to restrain children. >> they held me, like -- >> reporter: in pennsylvania, a group of students with behavioral issues described to abc news how they had been tied up or manhandled at previous schools. did it hurt? >> yeah, it really did hurt. >> reporter: 11-year-old jordan described being locked up in one of those isolation boxes. >> it's scary.